looking at the docs for the ibm 370 model 165 (https://bitsavers.org/pdf/ibm/370/systemGuide/GC20-1730-0_37... from 01970, several years before the model 168 mentioned above) i came across these more detailed notes on cpu performance

> The CPU has an 80-nanosecond cycle time and an 8-byte-wide data
path. (...) Among the major elements in the CPU are the instruction unit, the
execution unit, local storage, and control storage.

> (...) The faster internal performance of the Model 165 is due in part
to the use of more concurrence in CPU operations than is implemented
in the Model 65. The Model 165 CPU contains an instruction unit and
an execution unit that overlap instruction fetching and preparation
with instruction execution. The Model 165 instruction unit is
controlled by logic circuits and can process several instructions
concurrently while the execution unit is executing a single instruction.
The instruction unit prefetches instructions (maintaining them in
sequence), decodes instructions, calculates addresses, prefetches
instruction operands, and makes estimates of the success of conditional
branches. When a conditional branch is encountered, the instructions
immediately following the branch and those located at the branch address
are prefetched and placed in separate instruction buffers within the
instruction unit. Two 16-byte instruction buffers are used. This
insures the availability of prefetched instructions whether the branch
is taken or not.

> The execution unit is microprogram controlled and can execute one
instruction at a time. It has the capability of processing a new
instruction every cycle. Emphasis is placed on optimizing fixed binary
and floating-point arithmetic operations. A 64-bit parallel adder
is used to perform binary and floating-point arithmetic, while an 8-bit serial adder is used in the execution of packed decimal arithmetic.

processing a new instruction every 80-nanosecond cycle would be a peak performance of 12.5 mips, although presumably many instructions, in particular including multiplication, apparently took longer than that; i think the average was over 2 cycles per instruction. the 12.5 megahertz clock was the same on the model 168 i described above

i'm not an ibm fan. but ibm mainframes might be the central example of 'the kind of large computer a person at a university in the 01970s might be allocated a few hours a month on'

there's a wikipedia article about this particular model, mentioning it was discontinued in 01977: https://en.wikipedia.org/wiki/IBM_System/370_Model_165

there's a table at the end of https://www.ece.ucdavis.edu/~vojin/CLASSES/EEC272/S2005/Pape... describing the clock speed, cache size and associativity, cache line size, tlb size, etc., of numerous 360 and 370 models, including the 165 and 168, unfortunately lacking year of introduction. if someone else is doing this kind of investigation they may find it a useful reference

ken shirriff has an overview of the 360 line at http://www.righto.com/2019/04/iconic-consoles-of-ibm-system3...

nyt published an article on the introduction of the model 165 at https://www.nytimes.com/1970/07/01/archives/ibm-shows-2-new-... ('i.b.m. shows 2 new computers', gene smith, 01970-07-01) with the crucial detail:

A Model 165 with one million bytes would rent for $98,715 a month and sell for $4,674,160.

this allows us to calculate that, at the rental price and assuming 80% capacity utilization, each hour of effective computation cost 169 dollars

lynn wheeler's memoirs https://www.garlic.com/~lynn/subtopic.html are an irreplaceable source for information about this kind of thing; https://www.garlic.com/~lynn/2023b.html#0 discusses the history of development of the 370

in https://narkive.com/9nl6cj2Q.3 (which is by wheeler but which i can't find in his own web pages) he says the model 168 was 3.0 mips, while the 370/195 (which i think never shipped) reached 10 mips peak

http://www.beagle-ears.com/lars/engineer/comphist/model360.h... says the 370 model 168 was 1.6 cycles per instruction, reaching 3.5 mips on the model 168-3, although 12.5÷1.6 = 7.8, not 3.5

(why am i not an ibm fan? consider this quote from chris date about why his seminal book on databases was delayed for 2 crucial years from https://archive.computerhistory.org/resources/access/text/20... :

> I
wrote it very quickly, but I was in IBM. And for someone in IBM in those days to publish
something, it had to go through the clearance procedures in IBM. And so I submitted it to the
clearance procedure, and of course the problem with the book from an IBM point of view was
that it was not coming out saying that IMS was the greatest product ever invented. So
everybody who reviewed it in the clearance procedure did two things. First, they found
something I had to change. And second, they found somebody else who had to review it. This
process was clearly going to go on for a long time! (...) I did actually hawk a proposal and sample chapters around to several publishers,
and I got some proposed contracts, but I wasn’t getting the clearance.

)